The present invention relates to humidifiers and more specifically to the electrical control circuitry for the operation of a humidifier used in conjunction with a furnace. Humidifiers of this type typically utilize an electric motor to move air across a water-soaked evaporative pad. The humidifier is connected to the plenum of the furnace so that the humidifier air can be combined with the warm furnace air and distributed throughout the building.
These humidifiers generally use a transformer and an alternating current relay or a hybrid relay/transformer to operate the water solenoid valve and the fan motor. The 120 volt AC supply is interfaced with the furnace so power is present only when the furnace blower is operating. Typically, 120 volts of alternating current is supplied to a transformer with a low voltage output, usually 24 volts AC. The transformer or relay/transformer powers a secondary circuit which consists of a water solenoid valve and a humidistat in series. The humidistat switches to an on position when it senses a low moisture level in the air. When the furnace blower is on and the humidistat switch is closed, the fan motor for the humidifier is energized. Such a circuit is shown in FIG. 4.
Periodic maintenance of humidifiers of this type requires that the evaporative pad be changed. In the past, the entire humidifier was removed from the furnace plenum in order to obtain access to the evaporative pad. However, it is more desirable to be able to access the evaporative pad by merely removing a cover from the humidifier. To do this, it is necessary to have electrical components that are easily disconnected and reconnected.
It is an object of the present invention to provide a control circuitry for a humidifier that may be easily disconnected and reconnected during the periodic maintenance of the humidifier.